Just purchased the MPR419Q. Installing into my motorhome. Spliced in the wiring harness based on the diagram. It is all pretty straightforward. The unit does not power up. My tester shows current on the red wire. There is no current on the yellow. No current on the black. I tested the fuse at the back of the unit and in the motorhome fuse location. Both fuses are 10 amp. Both fuses tested good. I swapped out both fuses to make sure. I have tried current on the yellow wire with the key turned to the accessory position and the start position and with no key in the ignition. Thoughts?